Increased fluctuations in the path of the North Atlantic jet stream since the 1960s coincide with more extreme weather events in Europe such as heat waves, droughts, wildfires and flooding, reports a University of Arizona-led team.The research is the first reconstruction of historical changes in the North Atlantic jet stream prior to the 20th century. By studying tree rings from trees in the British Isles and the northeastern Mediterranean, the team teased out those regions' late-summer weather going back almost 300 years — to 1725.